May 19, 2015
Province Monitoring Red River Levels as Weekend Rain and Forecast Rain Moves North Through the Red River Basin
Manitoba Infrastructure and Transportation’s Hydrologic Forecasting Centre reports substantial rain of between 50 mm to 100 mm fell over the last few days across the Red River Basin. River levels over the next week will be carefully monitored for the possible operation of the Red River Floodway to lower river levels to help prevent basement sewer backup in the City of Winnipeg.
For the Red River, peak flows of 21,000 cubic feet per second (cfs) to 29,000 cfs are expected at Ste. Agathe. The first peak of about 21,000 cfs is expected to be noticed at Ste. Agathe within a day or two. The second peak, which is higher than the first peak, about 29,000 cfs, is expected within five to seven days. Future rain forecasts may require an adjustment in the high water levels.
The United States portion of the Souris River basin and a portion of the basin in south western Manitoba received precipitation between 50 to 90 mm.
The Qu’Appelle River and the upstream basin of the Assiniboine River, including the Shellmouth Reservoir basin has not received significant precipitation. Precipitation in those basins was less than 10 mm.
The effect of the precipitation is negligible on the upstream portion of the Assiniboine River near the Shellmouth Reservoir basin and the Qu’Appelle River basin. At this time, no operation changes are required for the Shellmouth Reservoir as water levels on the lower Assiniboine will continue to recede.
The effect of the precipitation will be minor on the Souris River basin. River levels have been rising in all portions of the Souris River basin within Manitoba. Levels are expected to be below the peak levels observed in late March due to spring runoff.
The Portage Diversion is not expected to be operated. The peak flow of the Assiniboine River at Portage is expected to be below 12,000 cfs. However, the river levels could be above the 10,000 cfs mark until the end of May.
High winds over the long weekend resulted in increases on south basin of Lake Manitoba levels of up to 3 feet at Westbourne, and on Lake Winnipeg the estimated high level wind set up reached 3.5 feet in the Gimli area.
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